检索结果-南通市图书馆

Open Journal of Soil Science 2024年第6期14卷 388-397页

作者： lloyd Murdock Anastasios Karathanasis Dottie Call Dana L. Dinnes Amitava Chatterjee Department of Plant & Soil Science University of Kentucky Lexington KY USA USDA-ARS National Laboratory for Agriculture and the Environment University Bldg Ames IA USA

A greenhouse experiment was conducted involving intact fragipan soil cores of 50 cm thickness after removing the topsoil horizons. The cores were maintained in moist condition throughout the experiment and received several treatments with various amendments for different periods ranging from 9 to 17 months. The amendments included annual ryegrass or Festulolium residues, powder limestone and various humate compounds alone or in combination with the grass residues. The results suggested a significant effect of ryegrass and Festulolium in reducing penetration resistance into the top 10 cm of the fragipan within 9 - 17 months, particularly when used in combination with certain humate materials such as Leonardite. Apparently, this is the result of the release of certain soluble organic compounds from the plant residues or the humate amendments that increase the solubility of Si and Al associated with the fragipan brittleness, thus decreasing the density of the compacted fragipan material.

关键词： Fragipan Fragipan Horizon Fragipan Soils Changing the Fragipan Annual Ryegrass Changes Fragipan Festulolium Changes Fragipan Amendments That Change the Fragipan

坦桑尼亚梅拉尼坦桑石矿床地质特征及成因模式

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

世界地质 2024年第3期43卷 353-362页

作者：孙国锋张明云闫红圃张猛张伟杰 lloyd Shawarira 河南省地质研究院郑州450001 河南省第二地质勘查院有限公司郑州450046 中金国检珠宝玉石质量检验中心有限公司广东深圳518020 津巴布韦地质调查局津巴布韦哈拉雷ZW192201

通过野外实地矿区地质填图,对坦桑尼亚梅拉尼坦桑石矿床的地质背景及矿区矿床地质特征进行详细描述,尤其对矿体及矿物宝石学特征进行了剖析和综述,探讨了宝石成因模式。认为坦桑石形成于约5亿年前的泛非运动,仅产于新元古代莫桑比克变... 详细信息

通过野外实地矿区地质填图,对坦桑尼亚梅拉尼坦桑石矿床的地质背景及矿区矿床地质特征进行详细描述,尤其对矿体及矿物宝石学特征进行了剖析和综述,探讨了宝石成因模式。认为坦桑石形成于约5亿年前的泛非运动,仅产于新元古代莫桑比克变质带的蚀变石墨片麻岩中,属于接触交代成因的矽卡岩矿床,主要受地层岩性和构造变形两个因素控制。

关键词：矽卡岩地质特征坦桑石成因模式梅拉尼

Unsupervised ore/waste classification on open-cut mine faces using close-range hyperspectral data

维普期刊数据库博看期刊

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2023年第4期14卷 89-99页

作者： lloyd Windrim Arman Melkumyan Richard J.Murphy Anna Chlingaryan Raymond Leung Rio Tinto Centre for Mine Automation Australian Centre for Field RoboticsThe University of SydneySydney 2006Australia

The remote mapping of minerals and discrimination of ore and waste on surfaces are important tasks for geological applications such as those in *** tasks have become possible using ground-based,close-range hyperspectral sensors which can remotely measure the reflectance properties of the environ-ment with high spatial and spectral ***,autonomous mapping of mineral spectra mea-sured on an open-cut mine face remains a challenging problem due to the subtleness of differences in spectral absorption features between mineral and rock classes as well as variability in the illumination of the *** additional layer of difficulty arises when there is no annotated data available to train a supervised learning algorithm.A pipeline for unsupervised mapping of spectra on a mine face is pro-posed which draws from several recent advances in the hyperspectral machine learning *** proposed pipeline brings together unsupervised and self-supervised algorithms in a unified system to map minerals on a mine face without the need for human-annotated training *** pipeline is eval-uated with a hyperspectral image dataset of an open-cut mine face comprising mineral ore martite and non-mineralised *** combined system is shown to produce a superior map to its constituent algo-rithms,and the consistency of its mapping capability is demonstrated using data acquired at two differ-ent times of day.

关键词： Hyperspectral imaging Mineral mapping Open-cut mine face Machine learning Convolutional neural networks Illumination invariance

The Utilization of the Generating Function Technique in the Discovery of Solutions for the Three-Dimensional Navier-Stokes Equation System

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Fluid Dynamics 2022年第1期12卷 86-95页

作者： Robert lloyd Jackson Independent Researcher Stilwell KS USA

The derivation of solutions to the Navier-Stokes (system of) equations (NSEs), in three spatial dimensions, has been an enigma as time can tell. This study wishes to show how to eradicate this problem via the usage of a recently proposed method for solving partial differential equations called the Generating Function Technique, or GFT for short. The paper will first quickly define the NSEs with and without an external force, then provide a quick synopsis of the GFT. Next, the study will derive solutions to these two major problems and give an analysis of the data concerning a specific set of criteria established by the Clay Mathematics Institute to determine the smoothness and existence of solutions. Results via GFT will show one can easily prove the existence of solutions to the NSEs with or without the presence of an external force. However, only the solutions to the NSEs will be globally bound.

关键词： Physics and Mathematics Fluid Mechanics Partial Differential Equations

CFD-DEM simulation of Small-Scale Challenge Problem 1 with EMMS bubble-based structure-dependent drag coefficient

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2021年第2期19卷 48-61页

作者： Musango Lungu John Siame lloyd Mukosha Multiphase Flow Research Group Chemical Engineering DepartmentSchool of Mines and Mineral SciencesCopperbelt UniversityKitwe 10101Zambia

In this study,the energy minimization multi-scale(EMMS)/Bubbling model is coupled with the computational fluid dynamics/discrete element method(CFD-DEM)model via a structure-dependent drag coefficient to simulate the National Energy Technology Laboratory(NETL)small-scale challenge problem using the open-source multiphase flow code *** numerical predictions are compared against particle velocity measurements obtained from high-speed particle image velocimetry(HSPIV)and differential pressure *** drag-reduction effect of the EMMS bubble-based drag coefficient is observed to significantly improve predictions of the horizontal particle velocity and granular temperature when compared to several other drag coefficients tested;however,the vertical particle velocity and pressure fluctuation characteristic predictions are *** drag-reduction effect is characterized by a reduction in the sizes of slugs or voids,as identified through spectral decomposition of the pressure ***,this study shows great promise in employing drag coefficients,developed via multi-scale approaches(such as the EMMS paradigm),in CFD-DEM models.

关键词： CFD-DEM Drag model EMMS/Bubbling model Fluidization Multi-scale

Arabidopsis Mutants and the Network of M icrotu bu le-Associated Functions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2008年第6期1卷 888-898页

作者： Henrik Buschmann Clive W. lloyd Department of Cell and Developmental Biology John Innes Centre 1 Colney Lane Norwich NR4 7UH UK

In early eukaryotes, the microtubule system was engaged in mitosis, intracellular transport, and flagellumbased motility. In the plant lineage, the evolution of a multicellular body involved the conservation of some core functions, the loss of others, and the elaboration of new microtubule functions associated with the multicellular plant habit. This diversification is reflected by the presence of both conserved （animal/fungi-like） and novel （plant-like） sequences encoding microtubule-related functions in the Arabidopsis genome. The collection of microtubule mutants has grown rapidly over recent years. These mutants present a wide range of phenotypes, consistent with the hypothesis of a functional diversification of the microtubule system. In this review, we focus on mutant analysis and, in particular, discuss double mutant analysis as a valuable tool for pinpointing pathways of gene function. A future challenge will be to define the complete network of genetic and physical interactions of microtubule function in plants. In addition to reviewing recent progress in the functional analysis of the ＇MAPome＇, we present an online database of Arabidopsis mutants impaired in microtubule functions.

关键词： cell division cell morphogenesis cytoskeleton genetics development Arabidopsis.

Pangenome analysis of Enterobacteria reveals richness of secondary metabolite gene clusters and their associated gene sets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Synthetic and Systems Biotechnology 2022年第3期7卷 900-910页

作者： Omkar S.Mohite Colton J.lloyd Jonathan M.Monk Tilmann Weber Bernhard O.Palsson The Novo Nordisk Foundation Center for Biosustainability Technical University of DenmarkKongens Lyngby2800Denmark Department of Bioengineering University of California San DiegoLa JollaCA92093USA

In silico genome mining provides easy access to secondary metabolite biosynthetic gene clusters(BGCs)encoding the biosynthesis of many bioactive compounds,which are the basis for many important drugs used in human ***,the association between BGCs and other functions encoded in the genomes of producers have remained ***,we present a systems biology workflow that integrates genome mining with a detailed pangenome analysis for detecting genes associated with a particular *** analyzed 3,889 enterobacterial genomes and found 13,266 BGCs,represented by 252 distinct BGC families and 347 additional singletons.A pangenome analysis revealed 88 genes putatively associated with a specific BGC coding for the colon cancer-related colibactin that code for diverse metabolic and regulatory *** presented workflow opens up the possibility to discover novel secondary metabolites,better understand their physiological roles,and provides a guide to identify and analyze BGC associated gene sets.

关键词： Pangenome analysis Workflow Secondary metabolites Colibactin Enterobacteria Secretion systems

Observer error in vegetation surveys:a review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2016年第4期9卷 367-379页

作者： lloyd W.Morrison Department of Biology Missouri State University901 S.National AvenueSpringfieldMO 65897USA National Park Service Heartland Inventory and Monitoring Program6424 W.Farm Road 182RepublicMO 65738USA

Aims Vegetation sampling employing observers is prone to both inter-observer and intra-observer *** types of errors are common:(i)overlooking error(*** observing species actually present),(ii)misidentification error(*** correctly identifying species)and(iii)estimation error(*** accurately estimating abundance).I conducted a literature review of 59 articles that provided quantitative estimates or statistical inferences regarding observer error in vegetation *** FindingsAlmost all studies(92%)that tested for a statistically significant effect of observer error found at least one significant *** surveys of species composition,mean pseudoturnover(the percentage of species overlooked by one observer but not another)was 10-30%.Species misidentification rates were on the order of 5-10%.The mean coefficient of variation(CV)among observers in surveys of vegetation cover was often several hundred%for species with low cover,although CVs of 25-50%were more representative of species with mean covers of>50%.A variety of metrics and indices(including commonly used diversity indices)and multivariate data analysis techniques(including ordinations and classifications)were found to be sensitive to observer *** of error commonly include both characteristics of the vegetation(*** size of populations,rarity,morphology,phenology)and attributes of the observers(*** fatigue,personal biases,differences in experience,physical stress).The use of multiple observers,additional training including active feedback approaches,and continual evaluation and calibration among observers are recommended as strategies to reduce observer error in vegetation surveys.

关键词： interobserver error intraobserver error misidentification pseudoturnover vegetation sampling

Nestedness in insular floras:spatiotemporal variation and underlying mechanisms

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2013年第6期6卷 480-488页

作者： lloyd W.Morrison Department of Biology Missouri State University901 S.National AvenueSpringfieldMO 65897USA

Aims Nestedness is a characteristic of insular metacommunity *** few studies,however,have attempted to evaluate temporal changes in nestedness,or elucidate the mechanisms underlying nestedness.I evaluated both spatial and temporal patterns of nestedness in the insular floras of four archipelagoes of small islands in the Bahamas and the potential underlying environmental *** The NODF(a nestedness metric based on overlap and decreasing fill)and the matrix temperature measure,T,were used to quantify nestedness in insular floras on small islands near Abaco,Andros,Great Exuma and the Exuma Cays,*** different null models were employed for each nestedness *** environmental variables were evaluated in relation to nestedness by ordering islands according to gradients and recalculating NODF *** Findings All archipelagoes were significantly *** among sites contributed more to overall nestedness than did nestedness among *** scores varied among archipelagoes,but were surprisingly constant over *** islands by vegetated area yielded the highest nestedness scores for three archipelagoes;ordering islands by protection from exposure yielded the highest nestedness score for one *** scores varied little over time even though species compositions changed,indicating that extinctions occurred in a deterministic *** relative importance of area suggests extinction is an important mechanism in producing *** to determine the relative importance of immigrations or extinctions requires some assumptions,however,and both processes are likely cumulative in most cases.

关键词： Bahamas environmental gradient insular floras nestedness NODF metric